WmiTraceMessageVa function (wdm.h)

Article
02/25/2022

The WmiTraceMessageVa routine adds a message to the output log of a WPP software tracing session.

Syntax

NTSTATUS WmiTraceMessageVa(
  [in] TRACEHANDLE LoggerHandle,
  [in] ULONG       MessageFlags,
  [in] LPCGUID     MessageGuid,
  [in] USHORT      MessageNumber,
  [in] va_list     MessageArgList
);

Parameters

[in] LoggerHandle

Specifies a trace handle for a software tracing session.

[in] MessageFlags

Specifies a bitwise OR of one or more message flags. See the Remarks section for details.

[in] MessageGuid

Specifies a GUID that identifies a software trace class.

[in] MessageNumber

Identifies the message subtype. The meaning of subtypes is specific to the software trace class and the provider.

[in] MessageArgList

Provides a required list of message parameters that specify a set of message parts. The parameters are organized as a sequence of parameter pairs, where each pair specifies one part of the complete message. Each parameter pair consists of a PVOID pointer to data, followed immediately by a ULONG value that specifies the length of the data. The parameter list must be terminated by a NULL PVOID pointer followed by a ULONG(0).

Return value

WmiTraceMessageVa returns one of the following values:

Return code	Description
STATUS_SUCCESS	The operation completed successfully.
STATUS_INVALID_HANDLE	LoggerHandle is not a valid software trace handle.
STATUS_NO_MEMORY	There is insufficient buffer memory to log the message. See the Remarks section for more information.
Other NTSTATUS value	An internal error occurred.

Remarks

A caller can use WmiTraceMessage or WmiTraceMessageVa to add a message to the output log of a WPP software tracing session. WmiTraceMessage simplifies a caller's code by handling the variable list mechanism before calling WmiTraceMessageVa.

A caller can set the following message flags:

Flag	Description
TRACE_MESSAGE_SEQUENCE	Include a sequence number in the message. Message sequencing can only be used if it is enabled for the software tracing session specified by LoggerHandle.
TRACE_MESSAGE_GUID	MessageGuid specifies a GUID that identifies a software trace class. This flag must be set.
TRACE_MESSAGE_TIMESTAMP	Include a time stamp in the message.
TRACE_MESSAGE_PERFORMANCE_TIMESTAMP	This flag is not implemented and is obsolete. It must not be used.
TRACE_MESSAGE_SYSTEMINFO	Include the thread identifier (TID) and process identifier (PID) in the message.

WmiTraceMessageVa does not log the message if one of the following is true:

The total size, in bytes, of the message data and the message header is greater than the size of individual message buffers allocated for a software tracing session. (The maximum message header size is 48 bytes.)
All message buffers allocated to software tracing session are full.

WmiTraceMessageVa runs at the IRQL of the caller.

Requirements

Requirement	Value
Minimum supported client	Available in Windows XP and later versions of Windows.
Target Platform	Universal
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
Library	NtosKrnl.lib
DLL	NtosKrnl.exe
IRQL	See Remarks section.